1. Technology Field
The present invention is related to a data writing method for the rewritable non-volatile memory module, and a memory control circuit unit and memory storage apparatus using the method.
2. Description of Related Art
Along with the widespread of digital cameras, cell phones, and MP3 in recently years, the consumers' demand for storage media has increased drastically. Since a rewritable non-volatile memory is characterized by non-volatility of data, low power consumption, small volume, non-mechanical structure, and fast reading and writing speed, the rewritable non-volatile memory is the most adaptable memory to be applied in a portable electronic product, e.g., a notebook computer. A solid state drive is a storage apparatus adopting flash memory as storage medium. Therefore, the flash memory industry has become a very popular part of the electronic industry in recent years.
In the rewritable non-volatile memory storage apparatus, for example, the solid state disk (SSD), when the spare blocks are exhausted, the control chip system of the SSD needs to move valid data fast and perform the garbage collection operation to obtain new spare blocks. The efficiency of the garbage collection operation not only effects the speed of writing, but also effects the write amplification rate and the lifespan of the SSD.
During the process of file writing, the system data (for example, the file allocation table (FAT)) and user data may be written into the SSD, interleavely. In the host side, the order for writing data is writing the data first and then updating the FAT. In the page base algorithm, the order for writing data into the flash memory is the same as the order for writing data into the flash memory in the host side. And, in the same physical erasing unit, because the updating of the FAT will cause the old FAT become invalid, there may have a lot of invalid data sections in the same one physical erasing unit. If those invalid data sections are accounted for 10% of the entire data, it represents that there are 90% of data which is needed to be moved during the garbage collection operation such that the efficiency of the garbage collection becomes low. Therefore, how to increase the efficiency of garbage collection is one of the major subjects that the person skilled in the art develops with the effort.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present invention. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art.